/*******************************************************************************************
 * Copyright (c) 2006-2009 Alex Robson, Rob Simmons, Craig Israel, and Rachel Twyford
 *
 * Use of this software in any form requires that you have both 
 * read and agreed to the following terms:
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the "Software"), 
 * to deal in the Software without restriction, including without limitation 
 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions: 
 *
 * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright notice, 
 * this list of conditions and the following disclaimer in the 
 * documentation and/or other materials provided with the distribution.
 * Neither the name of Nvigorate nor the names of its contributors may 
 * be used to endorse or promote products derived from this software without 
 * specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
 * DISCLAIMED. IN NO EVENT SHALL ANY CONTRIBUTOR BE LIABLE FOR ANY
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 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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using System.Collections.Generic;
using System.Data;
using System.Linq;
using Nvigorate.Common.Reflection;
using Nvigorate.Data;
using Nvigorate.Data.Query;
using Nvigorate.Extensions;
using Nvigorate.Relational.Mapping;
using Nvigorate.Relational.Mapping.Index;
using Nvigorate.Relational.Mapping.Interface;
using Nvigorate.Relational.Provider;
using Nvigorate.Relational.Repository;

namespace Nvigorate.Relational.Visitors
{
    public class PersistVisitor : IPersistableVisitor
    {
        #region Fields

        protected IDatabaseProvider _provider;
        protected IRepositoryMapIndex _repositoryMapIndex;
        protected IPersistenceKeyManager _keyManager;
        protected QueryList _queryResult = new QueryList();
        protected List<object> _visited = new List<object>();
        protected bool _enforceConcurrency;
        protected IPersistable _root;

        #endregion

        #region Constructor

        public PersistVisitor(IRepositoryMapIndex repositoryMaps, bool enforceConcurrency)

        {
            _repositoryMapIndex = repositoryMaps;
            _enforceConcurrency = enforceConcurrency;
        }

        #endregion

        #region Properties

        private IPersistenceKeyManager KeyManager
        {
            get
            {
                _keyManager = _keyManager ?? new PersistenceKeyManager(_repositoryMapIndex);
                return _keyManager;
            }
        }

        public TraversalDirection Direction
        {
            get { return TraversalDirection.BreadthFirst; }
        }

        #endregion

        #region Public Methods

        public void Visit(IPersistable persistable, IPersistable parent)
        {
            if (Visited(persistable))
                return;

            if (_root == null)
                _root = persistable;

            if (_visited.Contains(persistable.PersistenceTicket))
                return;

            KeyManager.RegisterType(persistable.InstanceType);
            KeyManager.RegisterPersistableInstance(persistable);

            VisitInstance(persistable, parent);
            _visited.Add(persistable.Instance);
        }

        public bool Visited(IPersistable persistable)
        {
            return _visited.Exists(i => ReferenceEquals(i, persistable.Instance));
        }

        public QueryList GetQuery()
        {
            return new QueryList
                       {
                           KeyManager.GetTableDeclarations(),
                           KeyManager.GetVariableDeclarations(),
                           _queryResult,
                           GetPersistManyToManyRelationships(),
                           KeyManager.GetTableSelection()
                       };
        }

        protected IQueryObject GetPersistManyToManyRelationships()
        {
            var manyToManyVisitor = new ManyToManyRelationshipVisitor(_keyManager, _repositoryMapIndex, Operation.Persist);
            _root.GetNavigator(_repositoryMapIndex).Accept(manyToManyVisitor);

            return manyToManyVisitor.GetQuery();
        }

        public List<string> GetTableVariableNames()
        {
            return KeyManager.GetTableVariableNames().ToList();   
        }

        public void PostPersist()
        {
            _keyManager.Persisted.Values.ForEach(persistable =>
                {
                    var map = _repositoryMapIndex.GetMap(persistable.InstanceType);
                    persistable.ClearDirtyState();
                    ClearStatefulLists(persistable, map);
                    map.MarkPersistedSources(persistable);
                    map.MarkTargetKeys(persistable);
                });
        }

        public void PopulateKeys(DataSet dataSet)
        {
            KeyManager.PopulateKeys(dataSet);
        }

        #endregion
        
        #region Private Methods

        private void VisitInstance(IPersistable persistable, IPersistable parent)
        {
            var bindingMap = _repositoryMapIndex.GetMap(persistable.InstanceType);
            if (bindingMap != null)
            {
                bindingMap
                    .GetSourceMapsInCreateOrder(Direction == TraversalDirection.DepthFirst ? true : false)
                    .ForEach(s => BuildQueryForSource(s, persistable, parent));
            }
        }

        private void BuildQueryForSource(ISourceMap sourceMap, IPersistable persistable, IPersistable parent)
        {
            var builder = PersistBuilder.GetBuilderForInstance(sourceMap, KeyManager, persistable, parent);
            _queryResult.Add(builder.Build(_enforceConcurrency));
        }
        
        private void ClearStatefulLists(IPersistable persistable, IBindingMap map)
        {
            map.Relationships.OfType<ManyToManyRelationship>()
                .Select(r => r.RelativeProperty ?? QueryBuilderHelper.GetDefaultChildPropertyName(r.SubjectType, r.RelativeType))
                .ForEach(p =>
                    {
                        var value = Reflector.Read(persistable.Instance, p) as IRelationshipChanges;
                        if(value != null)
                            value.ResetState();
                    });
        }

        #endregion
    }
}